Production of ethylidene chloride



Patented Feb. 12, 1935 I J ohan.Pieter Wibaut, Amsterdam, and Jan van Dalfsen, Rotterdam, Netherlands, assignors to The Dow Chemical Company, Midland, Mich}, a I

corporation of Michigan I No Drawing; Application samba-5,1933,

Serial No. 688,192

6 Claims. (01. z co- -ice) The present invention concernsan improved method of preparing ethylidene chloride through reacting hydr'ogenchloride with acetylene and/or vinyl chloride. 1

It is known'that vinyl chloride can be produced in high yield by contacting a gaseous mixture of hydrogen chloride and acetylene with mercuric chloride,.or.certain other catalysts, at elevated temperatures. During such reaction, as previ ously carried out, ethylidene chloride has sometimes been formed as a by-product, but only in relatively low yield. For instance, in German Patent No. 278,249 it is reported that when a gaseous mixture of hydrogen chloride and acetylene was passed over pumice impregnated with mercuric chloride and heated to between 150 C. and 220? 0., vinyl chloride was formed quantitatively. In British Patent No. 339,093 (1930) it is reported that, when a similar gaseous reaction mixture was passed over carbon impregnated with bismuth chloride and heated to about 200 C.,'there was formed morethan grams of vinyl chloride per hour and per liter of space occupied by the catalyst, alongwith from 8, to 10 grams of ethylidene chloride. When silica gel impregnated with antimony chloride was used under similar conditions ;in place of the carbon impregnated with bismuth chloride, ethylidene chloride was not formed. Said British patent further discloses that certain other substances, e. g. compounds of barium, silicon, calcium, magnesium, mercury, zinc, vanadium, aluminum, and iron are active catalysts for the reaction of hydrogen chloride with acetylene, but the patent does not disclose the nature or yields of the products formed when such other catalysts are used. While the above foreign patents describe methods which may, be excellent for the preparation of vinyl chloride from acetylene, it is obvious, from the low and only occasional yields of ethylidene chloridereported, that said methods are not well suited to the commercial production of ethylidene chloride as a major product.

' In United States Patent'No. 1,900,276 it is disclosed that, when a gaseous mixture 'of hydrogen chloride and vinyl chloride is passed through a tube, containing aluminum chloride heated to about C., ethylidene chloride is formed in between 20 and 40 per cent yield. I

We have now found that zinc chloride is a superior catalyst for the reaction of hydrogen chloride with vinyl chloride to form ethylidene chloride, but that zinc chloride, itself, is a relatively poor catalyst for the reaction of hydrogen chloride-with acetylene. Mercuric chloride, on the detail various waysin which the principle of the other hand, is an excellent catalyst for the formation of vinyl chloride fromacetylene-and hydrogen chloride, but a poor catalyst for the formation of ethylidene chloridefrom vinyl chloride and hydrogen chloride. We have'further found, however, that a mixture of acetylene and hydrogen chloride maybe contacted, either simultanee ously or consecutively, with mercuric chloride and zinc chlorideto form ethylidene chloride in good yield; I g

The invention, then, consistsin an improved method of reacting hydrogen chloride with acetylene and/or vinyl chloride to form ethylidene chloride and in certain catalysts particularly effective in promoting such reaction, said method and catalysts being hereinafter fully described and particularly pointed out in the claims. The following description and examples set forth in invention may be employed, but are not'to be con- 0 strued as limiting the invention.

' In preparing ethylidene chloride from acetyleneaccording to our'method, a mixture'of acetylene with preferably at least twice its molecular equivalent of gaseous hydrogen chloride is passed either simultaneouslyor consecutively over the catalysts mercuric chloride and zinc chloride supported on porous material, e. g. silica gel, tonethylidene chloride. The reactions may be carried out at any temperature sufiicient to cause reaction but low enough sothatthe reaction products are not appreciably decomposed. For instance said reactions have been found to proceed smoothly and without material by-product formation at temperatures between 25 and 200 C. However, the-reactions may be carried out most rapidly and smoothly at temperatures between about '75 and C. II I The product, ethylidene chloride,may be condensed directly from the reacted mixture in' nearly pure form, but, if desired, may be purified further by fractional distillation.

Instead of passing a mixture of acetylene with atleast twice its molecular equivalent of hydrogen chloride over the catalysts, as described above, a mixture of acetylene with a lesser quantity of hydrogen chloride may first be contacted with the mercuric chloride to form vinyl chloride, and thereafter additional hydrogen chloride may be added and the mixture be passed over zinc chloride to form ethylidene chloride. Also,

The runs described in the table of examples I were each made in accordance with the :following procedure:Acetylene 'or vinyl chloride, as

the case may be, was passed into a mixing chamher at a rate corresponding to 11.5liters' per hour at 18 C. and 760 millimeters pressure, end-dry hydrogen chloride gas was simultaneously passed into the mixing chamber ata rate corresponding to 2.2 liters per ,hourat the same temperature and pressure. The .-nrixed gasesflowed :thenoe through ,a reaction tube .filledwith ggmnularporous material, 1. e. silica :gel or activated ,charoQaLAimpregnatQd with amoximately, 41.1 male .per .100 grams of porous material of timely divided and substantially anhydrous mercuric chloride or zincchloride, or, in mm 7,-'with 0.1 mole 'of both of said compounds. During passage oi the gases, thewtube was maintained at the temperatures statedin (the table. making run, the gases were first through the heated tube for two hours so as thoroughly to saturate the porous material therewith, after which the yield of reaction prcductstformed during .a measured time interval, usuallyfive hours, was .carefiully m n d I g The genes, astheyissued from the reaction tube, were passed throngheaqueous calcium chloride, whereby excess hydrogen chloride was scrubbed from the gases and the-greater parttof the ethyli- .dene -.chloride was condensed as. aseparate liquid layer. ,The residual gases were dried bypassing them through a-tube filled with soda lime. The dried gases were then cooled to a temperature below l-8 C., wherebythe vinyl chlorideand residual ethylidene. chloride were condensed. The condensed materials were combined and fractionally distilled to separate and purify the vinyl chloride and-ethylidene chloride, and the quantities of the compounds weremeas- :u'red. 1

, The yield stated in the table is the .per cent oftheoretical, based on the quantity of the organic reactant employed.

Table R. 'Iem- Perlge'nft un peraye 0 N0. 3 time my] ethylidene 7 C. I chloride chloride 1 HgClHilicageL acetylene..- 25 :93 3 2 HgClzsilicagel acetylene 195 '98 1 3 HgCh-silicagel. aoetylene i0. 95, 4 HgClr-silicageL yinya l chloll 7 n e.

5 ZnClzsilicagel acetylene- M 19.12 5 Y 6, ZnOh-silioagcl. vinyd'l chlol00, 66

. n e. 7 HgCh-Zn C1zamylase; Mt '57. 3 30. 7

charcoal. r r

In the above table, runs 1 to 3 demonstrate that mercuricchloride is a highly active catalyst over a wide range of temperatures for the preparation of vinyl chloride from acetylene, but a poor catalyst, for the preparation otethylidene chloride from acetylene. Run 4 shows that mercuric chloride is a relatively poor catalyst for the preparation of ethylidene chloride from vinyl chloride. Runs 5 and 6 demonstrate that zinc chloride is a poor catalyst for the reaction of hydrogen chloride with acetylene, but .ahighly active catalyst for the reaction of hydrogen chloride with vinyl chloride. Run 7 demonstrates that hydro- .gen chloride can be reacted directly with acetylene "in the presence of porous material impregnated with-both i'mercuric r'chloride and zinc chloride to form, ethylidene chloridein' satisfactory yield. While wepreferto use finely divided and substantiallyganhydrous mercuric chloride and/or zinc chloride supported on a porous base asa catalyst forthe reactions herein described, since to the reaction, said catalytic compounds can be \used without a supporting base in any'other way, if desired.

The reactions herein describedlproceedsmodthty and K quite rapidly :at atmosphericpresslmahut, "if desired, pressures-above atmospheric be employed. In carrying out the reactions under.

,a maximum surface of catalyst is then exposed chloride or by diluting :thereactionmhrture with relatively inert, gases, e. g. .nitrogen, carbon dioxide, etc. However, in reacting acetylene with hydrogen chloride, it is; inadvisable to employ pressures higher than about BOpounds per "square inch.

Other modes of applyinglthe principle of (our invention maybe :employedinstea-d-of those explained, change being made as regards the method disclosed, provided the step or steps statedjbyany of the following claims orthe "equivalent of such stated step or steps-10c employed.

We therefore "particularly point out and-mstinctlyclaim as'om' inventionr 1. In :a method of making ethylidene chloride, the istep'wh'ich consists n51 reacting vinyl-chloride with hydrogen chloride in theip'resenoe zinc :chlonide. J

:2. In :a method of making eth'ylid'ene chlm'tde, the step which consists-in reacting vinyl chloride with hydrogen chloride in the presence or zinc chloride vsupported on porous and substantially inert carrier material.

I '3. In a method of making ethylidene chloride, the step which consists 'in reacting vinyl chloride with hydrogen chloride in the presence of finely divided and substantially anhydrous zinc-chloride supported on porous carrier material.

4. In a method of making ethylidene chloride, the steps which consist in passing a mixtine of acetylene and hydrogen chloride over mercuric chloride and zinc chloride supported on porous and substantially inert carrier material at areaction temperature,. separating ethylidene chloride from the reacted mixture, and recycling the residual mixture overthe catalyst asdescribed above. v J

, 5. In a method ,of making ethylidene chloride, the steps whichv consist in passing amixture 0t acetylene with at least twice its molecular, equivalent of hydrogen chloride over finely divided and substantially anhydrous mercuric and zinc chlorides supported on porousland substantially inert carrier material ata reaction temperature, condensing ethylidenechloridefrom the reacted and substantially inertmixture, and recycling the residual mixture over the catalyst. I

6. In a method of making ethylidene chloride,

the steps which consist in passing a. mixture of 5 acetylene with at least twice its molecular equivalent; of hydrogen chloride consecutively over finely divided and substantially anhydrous mercuric and zinc chlorides supported on porous and substantially inert carrier material at a reaction temperature, condensing ethylidene chloride from the reacted mixture and recycling the residual mixture over the catalyst.

JOHAN PIETER WIBAUT. JAN VAN DALFSEN. 

